fix another test

Author: RalfJung

src/test/ui/issues/issue-54348.rs

@@ -2,6 +2,6 @@
 
 fn main() {
     [1][0u64 as usize];
-    [1][1.5 as usize]; //~ ERROR index out of bounds
-    [1][1u64 as usize]; //~ ERROR index out of bounds
+    [1][1.5 as usize]; //~ ERROR operation will panic
+    [1][1u64 as usize]; //~ ERROR operation will panic
 }

src/test/ui/issues/issue-54348.stderr

@@ -1,16 +1,16 @@
-error: index out of bounds: the len is 1 but the index is 1
+error: this operation will panic at runtime
   --> $DIR/issue-54348.rs:5:5
    |
 LL |     [1][1.5 as usize];
-   |     ^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1
    |
-   = note: `#[deny(const_err)]` on by default
+   = note: `#[deny(panic)]` on by default
 
-error: index out of bounds: the len is 1 but the index is 1
+error: this operation will panic at runtime
   --> $DIR/issue-54348.rs:6:5
    |
 LL |     [1][1u64 as usize];
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1
 
 error: aborting due to 2 previous errors